Superior PetSafe® UltraSmart In-Ground Pet Fence keeps dogs safely contained in the yard with improved features like the UltraSmart rechargeable collar—30% smaller and lighter than other PetSafe® collars. Also features exclusive 24/7 battery backup. High-powered transmitter contains dogs in an area up to 1/3 acre! Fully compatible with PetSafe® PawzAway® indoor pet-proof barriers.